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FIGURE 11 in A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)

FIGURE 11. Daphnia chevreuxi, adult male from Stagno di C. da Buffali (Nebrodi, Cesarò), Sicily, Italy: A–B, lateral and latero-ventral view. C. ventral view. D. head. E, postabdomen. F, its distal portion. G, distal portion of antenna I. H, central portion of body, ventral view. Scale bars: 1 mm for A–C; 0.1 mm for D–F, H; 0.01 mm for G.

FIGURE 7 in A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)

FIGURE 7. Daphnia chevreuxi, thoracic limbs of adult parthenogenetic female from Stagno di C. da Buffali (Nebrodi, Cesarò), Sicily, Italy: A, limb III. B. seta 2 of its exopodite. C–D, its inner-distal portion. E, limb IV. F, its inner-distal portion. G, limb V. H, its distal portion. Scale bars 0.1 mm.

FIGURE 5 in A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)

FIGURE 5. Daphnia chevreuxi, adult parthenogenetic female from Stagno di C. da Buffali (Nebrodi, Cesarò), Sicily, Italy: A–B, rostrum and antenna I. C–D, antenna II. E–F, coxal portion. G, distal portion of basal segment. Scale bars: 1 mm C; 0.1 mm for A–B, D–G.

FIGURE 3 in A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)

FIGURE 3. Daphnia chevreuxi from «Environs de Bòne», sample DGF 0783 (A–F) and «Environs du Bòne, Abreuvoir», sample DGF 0730 (D), Algeria: A–B, large adult parthenogenetic female. C–D, head, lateral view. E, juvenile female, instar I. F, juvenile female. G, ephippium. Scale bars 1 mm.

FIGURE 6 in A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)

FIGURE 6. Daphnia chevreuxi, head and thoracic limbs of adult parthenogenetic female from Stagno di C. da Buffali (Nebrodi, Cesarò), Sicily, Italy: A, maxilla I. B–C, limb I. D, its outer distal lobe. E, limb II. F, its gnathobase. Scale bars 0.1 mm.

FIGURE 9 in A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)

FIGURE 9. Daphnia chevreuxi, ephippial female from «Environs de Bòne. Abreuvoir», sample DGF 0767, Algeria: A, carapace with ephippium. B–D, ephippium sculpture. Scale bars: 0.1 mm for A–C; 0.01 mm for D.

FIGURE 2 in A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)

FIGURE 2. Daphnia chevreuxi, female from Stagno di C. da Buffali (Nebrodi, Cesarò), Sicily, Italy: A–B, adult parthenogenetic female. C, ephippial female. D, head, lateral view. E, head shield, dorsal view. F, fornix. G, juvenile female. Scale bars: 1 mm A–E; 0.1 mm for F–G.

FIGURE 1 in A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)

FIGURE 1. Daphnia chevreuxi, adult parthenogenetic female from "Environs de Bòne", Algeria, sample DGF 0783 (A–B) and Stagno di C. da Buffali (Nebrodi, Cesarò), Sicily, Italy (C–G): A, large adult female. B, its head. C, postabdomen. D, abdomen. E, distal portion of postabdomen. F, limb I. G, gnathobase of limb II. H, limb V. Scale bars: 1 mm A; 0.1 mm for B–H.

opencc-zeroApr 2022View details →

Data from: Competitive consequences determined by phenotypic but not genetic distance: a study with asexual Daphnia genotypes

1. How evolutionary relatedness influences the strength of competitive interactions among genetically isolated populations has been a long-standing interest in ecology. Darwin's "Competition Relatedness Hypothesis (CRH)" states that, since closely related species should compete more strongly, they are less likely to coexist, while Herbert's "Bimodal Competition Hypothesis (BCH)" predicts that competitive exclusion is less likely to occur when the competing species are genetically close or distant. 2. To test these hypotheses, we experimentally examined the difference in the competitive ability and life tables of fecundity and survivorship among four different genotypes of asexual Daphnia cf. pulex that diverged from a single ancestral genotype. 3. The experiments showed that the competitive consequences differed depending on the pairing of the competing genotypes, and that the degree of the competitive exclusion was lower when the competing genotypes were genetically closer to each other. These results partially supported the BCH but not the CRH at all. More importantly, the degree of competitive exclusion was better predicted by the phenotypic rather than genetic distances between the competing genotypes. 4. The life table experiments revealed that competitively inferior genotypes had higher early reproduction rates, but survival rates decreased with age and thus body size, probably a result of selection by predation pressures found in nature. 5. These results indicate that competitive superiority is highly dependent on selection pressures that given organisms have been evolutionally subjected to, and, that genetic similarity is not necessarily an appropriate measure for predicting the completive exclusion on an ecological time scale. To predict competitive relationships among the organisms, it is essential to comprehend their phenotypic differences rather than simply knowing their genetic or phylogenetic relationships.

opencc-zeroApr 2022View details →

Historical exposure to chemicals reduces tolerance to novel chemical stress in Daphnia (waterflea)

Until the last few decades, anthropogenic chemicals used in most production processes didn't have a comprehensive assessment of their risk and impact on wildlife and humans. They are transported globally and usually end up in the environment as unintentional pollutants causing long-term adverse effects. Modern toxicology practises typically use acute toxicity tests of unrealistic concentrations of chemicals to determine their safe use, missing pathological effects arising from long-term exposures to environmentally relevant concentrations. Here, we study the transgenerational effect of environmentally relevant concentrations of five chemicals on the priority list of international regulatory frameworks on the keystone species Daphnia magna. We expose Daphnia genotypes resurrected from the sedimentary archive of a lake with a known history of chemical pollution to the five chemicals to understand how historical exposure to chemicals influences adaptive responses to novel chemical stress. We measure within and transgenerational plasticity in fitness-linked life history traits following exposure of 'experienced' and 'naive' genotypes to novel chemical stress. As the revived Daphnia originates from the same genetic pool sampled at different times in the past, we are able to quantify the long-term evolutionary impact of chemical pollution by studying genome-wide diversity and identifying functional pathways affected by historical chemical stress. Our results suggest that historical exposure to chemical stress causes reduced genome-wide diversity, leading to lower cross-generational tolerance to novel chemical stress. Lower tolerance is underpinned by reduced gene diversity at detoxification, catabolism and endocrine genes in experienced genotypes. We show that these genes sit within pathways that are conserved and potential chemical targets in other species, including humans.

opencc-zeroMay 2022View details →

Evolutionary change in metabolic rate of Daphnia pulicaria following invasion by the predator Bythotrephes longimanus

Metabolic rate is a trait that may evolve in response to the direct and indirect effects of predator-induced mortality. Predators may indirectly alter selection by lowering prey densities and increasing resource availability or by intensifying resource limitation through changes in prey behaviour (e.g. use of less productive areas). In the current study we quantify evolution of metabolic rate in the zooplankton Daphnia pulicaria following an invasive event by the predator Bythotrephes longimanus in Lake Mendota, Wisconsin, US. This invasion has been shown to dramatically impact D. pulicaria, causing a ~60% decline in their biomass. Using a resurrection ecology approach, we compared the metabolic rate of D. pulicaria clones originating from prior to the Bythotrephes invasion with that of clones having evolved in the presence of Bythotrephes. We observed a 7.4% reduction in metabolic rate among post-invasive clones compared to pre-invasive clones, and discuss the potential roles of direct and indirect selection in driving this change.

opencc-zeroAug 2022View details →

The cDNA sequence data of hox genes in Daphnia similoides sinensis

Hox genes are important regulatory factors of transcription in metazoans, and are involved in the growth and development of organisms. In this study, the effects of Microcystis aeruginosa on Hox gene expression in the mothers and offspring of Daphnia similoides sinensis were investigated using a mixed diet of M. aeruginosa and Scenedesmus obliquus in two clones. The 14 Hox genes sequence were identified in D. similoides sinensisare through the previous transcriptome data (Zhang et al., 2016. DOI: 10.1038/srep34241).

opencc-by-4.0May 2024View details →

Daphnia magna XINB3 v.3.0 genome assembly

Genome assembly of the FI-XINB3 genotype.

opencc-by-4.0Apr 2023View details →

Variation in defensive spines across juvenile instars of Daphnia magna

This is the data set and R-script of the corresponding publication.

FIGURE 2 in Invasion of a Holarctic planktonic cladoceran Daphnia galeata Sars (Crustacea: Cladocera) in the Lower Lakes of South Australia

FIGURE 2. Morphology of Daphnia (Daphnia) galeata from Lake Albert (A-B) and Lake Alexandrina (C-F), South Australia. A, invader D. galeata (1) together with two indigenous taxa, D. lumholtzi (2) and D. cf. carinata (3). B, anterior body half. C- D, two different females. E, head. F, postabdomen. Scale bar 0.1 mm (except of A).

FIGURE 1 in Invasion of a Holarctic planktonic cladoceran Daphnia galeata Sars (Crustacea: Cladocera) in the Lower Lakes of South Australia

FIGURE 1. Sampled water bodies in Australia. A–B, position of the Lower Lakes in Australia. C-D, recent state of Lake Albert. E, Lake Alexandrina at Tauwitcherie barrage during the 2001-2010 drought. Look at the water level of these two lakes. B, from Google Earth; E, courtesy of the ABC News (Australian Broadcasting Corporation).

FIGURE 4 in Invasion of a Holarctic planktonic cladoceran Daphnia galeata Sars (Crustacea: Cladocera) in the Lower Lakes of South Australia

FIGURE 4. Split network of haplotypes of the mitochondrial cytochrome c oxidase subunit I (COI) gene in Daphnia galeata.

FIGURE 3 in Invasion of a Holarctic planktonic cladoceran Daphnia galeata Sars (Crustacea: Cladocera) in the Lower Lakes of South Australia

FIGURE 3. Maximum likelihood tree of the subgenus Daphnia (Daphnia) based on combined data on the 12S + 16S mitochondrial gene sequences, with D. (Ctenodaphnia) magna as an outgroup. The support values of individual nodes are based on: Maximum likelihood (ML)/ Maximum Parsimony (MP)/Bayesian Inference (BI).

opencc-by-4.0Dec 2018View details →

Supporting data and code for: Dissecting the transcriptomic basis of phenotypic evolution in the aquatic keystone grazer Daphnia: Part I

Main codes for Dissecting the transcriptomic basis of phenotypic evolution in the aquatic keystone grazer Daphnia.